Basis of Presentation (Policies)

6 Months Ended

Dec. 31, 2012

Basis of Presentation [Abstract]

Basis of Presentation [Policy Text Block]

The accompanying consolidated statement of financial condition as of June 30, 2012 was derived from the audited consolidated financial statements of Greene County Bancorp, Inc. (the "Company") and its wholly owned subsidiary, The Bank of Greene County (the "Bank") and the Bank's wholly owned subsidiary, Greene County Commercial Bank and Greene Property Holdings, Ltd.The consolidated financial statements at and for the three and six months ended December 31, 2012 and 2011 are unaudited.

The financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America ("GAAP") for interim financial information and with the instructions to Form 10-Q and Article 8 of Regulation S-X.  Accordingly, they do not include all of the information and notes required by GAAP for complete financial statements.  To the extent that information and notes required by GAAP for complete financial statements are contained in or are consistent with the audited financial statements incorporated by reference to Greene County Bancorp, Inc.'s Annual Report on Form 10-K for the year ended June 30, 2012, such information and notes have not been duplicated herein.  In the opinion of management, all adjustments (consisting of only normal recurring items) necessary for a fair presentation of the financial position and results of operations and cash flows at and for the periods presented have been included.   Amounts in the prior year's consolidated financial statements have been reclassified whenever necessary to conform to the current year's presentation.  These reclassifications, if any, had no effect on net income or retained earnings as previously reported.  All material inter-company accounts and transactions have been eliminated in the consolidation. The results of operations and other data for the three and six months ended December 31, 2012 are not necessarily indicative of results that may be expected for the entire fiscal year ending June 30, 2013.   These consolidated financial statements consider events that occurred through the date the consolidated financial statements were issued.

Allowance for Loan Losses [Policy Text Block]

Greene County Bancorp, Inc.'s critical accounting policies relate to the allowance for loan losses and the evaluation of securities for other-than-temporary impairment. The allowance for loan losses is based on management's estimation of an amount that is intended to absorb losses in the existing loan portfolio. The allowance for loan losses is established through a provision for loan losses based on management's evaluation of the risk inherent in the loan portfolio, the composition of the portfolio, specific impaired loans and current economic conditions. Such evaluation, which includes a review of all loans for which full collectibility may not be reasonably assured, considers among other matters, the estimated net realizable value or the fair value of the underlying collateral, economic conditions, historical loan loss experience, management's estimate of probable credit losses and other factors that warrant recognition in providing for the allowance of loan losses. However, this evaluation involves a high degree of complexity and requires management to make subjective judgments that often require assumptions or estimates about highly uncertain matters. This critical accounting policy and its application are periodically reviewed with the Audit Committee and the Board of Directors.

Securities [Policy Text Block]

Securities are evaluated for other-than-temporary impairment by performing periodic reviews of individual securities in the investment portfolio. Greene County Bancorp, Inc. makes an assessment to determine whether there have been any events or economic circumstances to indicate that a security on which there is an unrealized loss is impaired on an other-than-temporary basis. The Company considers many factors, including the severity and duration of the impairment; the intent and ability of the Company to hold the security for a period of time sufficient for a recovery in value; recent events specific to the issuer or industry; and for debt securities, intent to sell the security, the likelihood to be required to sell the security before it recovers the entire amortized cost, external credit ratings and recent downgrades. The Company is required to record other-than-temporary impairment charges through earnings, if it has the intent to sell, or will more likely than not be required to sell an impaired debt security before a recovery of its amortized cost basis. In addition, the Company is required to record other-than-temporary impairment charges through earnings for the amount of credit losses, regardless of the intent or requirement to sell. Credit loss is measured as the difference between the present value of an impaired debt security's cash flows and its amortized cost basis. Non-credit related impairment must be recorded as decreases to accumulated other comprehensive income as long as the Company has no intent or requirement to sell an impaired security before a recovery of amortized cost basis.